FDCA is a very promising compound which can be produced via biological pathways and which is a useful starting compound for various chemical compounds.
Various methods for the production of FDCA are known, some of them by various chemical synthesis steps, others by fermentation of suitable starting compounds, such as hydroxymethyl furfural (HMF) (WO 2012/064195).
One of the disadvantages of the enzymatic preparation of FDCA is the difficulty of removing contaminants from the product to produce a substantially pure FDCA. More in particular it has been found to be very difficult to remove the monocarboxylic acid from the final product, for example when using the conventional acid precipitation.
It is one of the objects of the invention to provide a process for producing substantially pure FDCA by fermentation having a very low mono carboxylic acid content.